1. Summary of the Invention
The present invention generally relates to medical devices and more particularly relates to surgical instruments.
2. Description of the Prior Art
The diagnostic advantages of obtaining and analyzing a tissue sample have been long known. This procedure is often termed biopsy. To be most useful, the surgical instrument or biopsy needle, utilized to obtain the tissue sample must be insertable through the skin of the patient, guidable through the body to the sample site, and capable of quickly and easily excising and removing the selected sample.
An early biopsy instrument is seen in U.S. Pat. No. 3,577,979, issued to van der Gaast, incorporated herein by reference. Called a disposable surgical skin punch by the inventor, the device is capable of taking manual core samples. U.S. Pat. No. 4,940,061, issued to Terwilliger et al., incorporated herein by reference, shows an extremely complex motorized version of a biopsy instrument. Though probably somewhat easier to operate, the cost of manufacturing such a device probably precludes disposable use, which has become a major health care consideration. Unlike the earlier device, Terwilliger et al. employs a stylet having a tissue notch concentrically slidable within a sharpened canula. This basic sampling technique has become the standard technique.
To facilitate maintenance of the tissue excising portion of the needle, U.S. Pat. No. 5,031,634, issued to Simon and incorporated herein by reference, shows the use of retractable barbs at the distal end. This may be particularly adapted to soft tissue use, particularly the breast. U.S. Pat. No. 5,036,860, issued to Leigh et al., incorporated herein by reference, shows a device especially intended to be disposable following single use. With the increasing awareness of blood borne viruses, disposability is now a key feature.
U.S. Pat. No. 5,125,413, issued to Baran and incorporated herein by reference, describes a spring loaded device permitting single hand operation by attending medical personnel. Before use, the spring is compressed providing retraction of the outer canula proximally of the distal stylet tip. The distal end of the instrument is advanced to the sample site. Releasing the spring advances the sharpened canula over the stylet thus excising the tissue sample within the sample notch (see FIG. 9). This has become the typical method for biopsy procedures. Alternative tissue notch configurations are shown in U.S. Pat. No. 5,127,419, issued to Kaldany.